四倍体刺槐的生物量及营养动态分析

为了更好地了解四倍体刺槐(tetraploid Robinia pseudoacacia)生长季节的生物量和营养质量分数动态变化,为确定其饲料林的最佳刈割时期提供理论依据,在测定1～2年生林分生长时期叶片营养的基础上,测定了3年生林分的株高、基径和叶质量、茎质量动态,并分析了此林分的叶片、茎杆和整株的营养动态。结果表明:叶片和茎杆生物量的变化与株高和基径生长动态相似,均在6月25日前增加迅速,然后进入缓慢生长期,最后从8月10日再次快速生长;不同年份的叶片营养质量分数具有相似的变化趋势;在整个生长过程中,叶片的粗蛋白质量分数最高,茎杆最低,且粗蛋白质量分数从6—7月份下降迅速,随后逐渐下降;叶片、茎杆和整株的干物质、中性洗涤纤维和酸性洗涤纤维质量分数在生长季节逐渐增加,而且均在叶片中质量分数最低、茎杆中最高。综合考虑叶片及当年生茎杆生物量和粗蛋白质的相互变化,确定四倍体刺槐第1次最佳刈割时期为6月下旬。     

Q fever in pregnant goats: humoral and cellular immune responses

Q fever is a zoonosis caused by the intracellular bacterium Coxiella burnetii. Both humoral and cellular immunity are important in the host defence against intracellular bacteria. Little is known about the immune response to C. burnetii infections in domestic ruminants even though these species are the major source of Q fever in humans. To investigate the goat’s immune response we inoculated groups of pregnant goats via inhalation with a Dutch outbreak isolate of C. burnetii. All animals were successfully infected. Phase 1 and Phase 2 IgM- and IgG-specific antibodies were measured. Cellular immune responses were investigated by interferon-gamma, enzyme-linked immunosorbent spot test (IFN-γ Elispot), lymphocyte proliferation test (LPT) and systemic cytokines. After two weeks post inoculation (wpi), a strong anti-C. burnetii Phase 2 IgM and IgG antibody response was observed while the increase in IgM anti-Phase 1 antibodies was less pronounced. IgG anti-Phase 1 antibodies started to rise at 6 wpi. Cellular immune responses were observed after parturition. Our results demonstrated humoral and cellular immune responses to C. burnetii infection in pregnant goats. Cell-mediated immune responses did not differ enough to distinguish between Coxiella-infected and non-infected pregnant animals, whereas a strong-phase specific antibody response is detected after 2 wpi. This humoral immune response may be useful in the early detection of C. burnetii-infected pregnant goats.     

侧柏叶温及叶绿素荧光特性对土壤水分胁迫的响应简

为了研究土壤水分与植物生长间的关系,以侧柏为材料进行盆栽试验,人工控制土壤水分,设置4个水分梯度（正常供水、轻度水分胁迫、中度水分胁迫、重度水分胁迫）,测定其叶温和叶绿素荧光参数.结果表明：随着干旱胁迫的加剧,叶温和非光化学淬灭升高;初始荧光F0总体上表现为逐渐上升的趋势;而最大荧光Fm、可变荧光Fv、PSⅡ最大原初光化学量子效率Fv/Fm、PSⅡ的潜在活性Fv/F0、PSⅡ实际光化学量子效率和表观光合电子传递速率均表现为下降.参数的日变化呈现单峰型曲线：PSⅡ实际光化学量子效率和非光化学淬灭的日变化曲线为凹形,而表观光合电子传递速率日变化曲线为凸形.可知干旱胁迫导致PSⅡ的电子传递效率降低,降低了光能利用率,影响其光合作用.     

最优控制与系统仿真

仿真模型的参数调整通常是由模型研制者完成,本课题组研制的森林资源监测系统模型的参数调试者是用户,本文所介绍的计算机自动调试技术的原理、技术及实现,是本课题组开拓的一个崭新领域。此法已研制成软件,在实践中应用效果良好。     

Testing predator-driven evolution with Paleozoic crinoid arm regeneration

Regenerating arms of crinoids represent direct evidence of nonlethal attacks by predators and provide an opportunity for exploring the importance of predation through geologic time. Analysis of 11 Paleozoic crinoid Lagerst?tten revealed a significant increase in arm regeneration during the Siluro-Devonian. During this interval, referred to as the Middle Paleozoic Marine Revolution, the diversity of shell-crushing predators increased, and antipredatory morphologies among invertebrate prey, such as crinoids, became more common. Crinoid arm regeneration data suggest an increase in nonlethal attacks at this time and represent a causal link between those patterns, which implies an important role for predator-driven evolution.     

日本柳杉髓心方材高频真空干燥试验

该文对日本人工林柳杉髓心方材进行系列高频真空干燥试验,掌握不同高频真空干燥条件下柳杉髓心方材的干燥特性并对干燥缺陷进行分析.结果表明,柳杉髓心方材虽难干燥,但在高频真空干燥前对木材进行合理的处理,如蒸汽和过热蒸汽预处理、沿木材长度方向制作一定深度和宽度的切口等,可有效地提高干燥质量,尤其是可减少开裂的产生.     

Carbon tetrachloride: a new crystalline modification

X-ray and optical studies of single crystals of carbon tetrachloride have established the existence of a previously unreported rhombohedral modification stable between the melting point and the transition temperature. The discovery of this phase emphasizes the need for a careful reinterpretation of available measurements of the thermal properties of solid carbon tetrachloride.